How 'bout any ignition components that might have been used with both your electronic and points ignitions? Cap, rotor, wires, plugs, coil? Keep in mind that "new" doesn't necessarily mean "good".

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

How could I test for this? I used new springs and new vales and guide liners were put in as well.
I agree about the new not necessarily being any good, easy to make assumptions and miss things if something out of the box is no good. In terms of parts crossover between the two distributors, the points one is an Aussie Bosch model so none of the parts are interchangeable.


What if one or two lobes on the cam are off by a bit, its not very likely, but could that cause random misfire or would it be more regular?

Here is another long shot: years ago on my early Duster, I had a carb gasket that was too soft, and the surface that sealed against the base of the carb expanded up into the vacuum passages that were formed between the carb base and the gasket, thus cutting off part of the idle circuit.

My reaction to your vacuum numbers is that the idle value is too low. I think something is wrong there. It should be idling at 18. Did you check the voltage at the ballast resister? Check to see if there is a correlation between the miss and a voltage fluctuation there.

Edit: I've thought about this some more, and wonder if your harmonic balancer has slipped and is no longer aligned correctly? Your low vacuum reading suggests incorrect timing.

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Hi,
I will keep an eye on the gaskets, The carb has been on and off the engine numerous times so I believe they are fine.
There do not appear to be any voltage fluctuations in the 12v system at the ignition. I checked the balancer when I had the degree wheel on, it then cracked its snout so there is a new powerbond one on there, I checked the timing marks against the old balancer before fitting.

A sound recording (with or without video) of the exhaust at the tailpipe will help with diagnosis.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Hi,
Here's a sound clip at the tailpipe.
https://youtu.be/e2ujmWXdSKI
Thanks

That sounds like some sort of sticking valve problem. An engine is an air pump- your vac gauge reading results from each piston pulling down against the restriction of the carb throttle blade. Even "pulls" from all cylinders = a steady vac needle. Most any ignition or fuel faults won't affect the engine's ability to pump, so the vacuum reading will still be steady.

If there is BAD compression on one hole from a leaking valve (or a hole in the piston)- you'll get a steady rhythmic pulse in the vac needle. (either the "pull" is absent, or the int valve leaks back into the intake manifold) An irregular jump in the vac needle shows that there is an irregular fault in compression. Possibilities could be a tight valve guide to stem, or a valve that's not perfectly concentric to it's seat. (since you loosened up valve lash, I think you'd have noticed a broken valve spring).

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63 Valiant Wagon
225 - 4 bbl

The exhaust clip doesn't sound too bad at all. There's a random occasional misfire, yes, but not a terrible one. That's the good news. The bad news is, there's nothing characteristic about what I hear that points to any particular cause. I don't hear anything that points to a sticking valve(s), I don't hear anything that points to a vacuum leak, I don't hear anything that points to cam trouble, etc.

Sorry!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Oh well, I will keep looking for the problem, I have an HT probe coming that may show something.
Thank you for taking the time to help.
Will

Hi all,
I have been looking at my distributor cap and I note that the spark has been jumping from the rotor out to the posts but also up to the posts to a greater or lesser extent on all six posts. The posts also have some pitting where the spark is jumping too this is a bluestreak cap with the brass posts and has only done a couple of hundred miles, I wouldn't have thought there should be any pitting so soon but I dono, interestingly one post only has spark marks and no pitting, I will have another look at this post tonight when I get a chance, see if i can figure out a reason for this.
One last thing the spark marks on the rotor and the posts indicate that the spark is jumping off of the rear (anti-clockwise side) of the rotor, I think the ignition is firing as the rotor is moving away from the post, I scoped the secondary ignition firing line and something weird is happening as the spark tries to jump inside the distributor there are big voltage spikes as it begins to jump, much higher than the spark plug ionization voltage. I am wondering if the rotor to reluctor phasing is off, I will check that this weekend hopefully.
Apologies for the rambling post so does any of this seem indicative of a problem (all of it perhaps! haha)?
Thanks

I wouldn't expect to see pitting in the posts after a few hundred miles, actually not at all, maybe your onto something with the reluctor/voltage spikes.

brian

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